The present invention is generally related to radiotelephones, and more particularly to electromagnetic shielding apparatus for cellular telephones.
Cellular telephones and other electronic equipment, such as, for example, computers and microwaves, generate electromagnetic signals which may radiate to and interfere with another portion of that equipment or with another piece of electronic equipment located nearby. To minimize such interference, electrically conducting material in the form of a shield is typically interposed between the source of electromagnetic signals and the circuitry subject to interference. Such shields may take the form of a wall or a complete enclosure placed around the source of electromagnetic signals and/or around the circuitry subject to interference. For example, opposite sides of a circuitry board may be shielded from one another by enclosing each side of the circuit board by a housing portion having a conductive surface, as illustrated, for example, in U.S. Pat. No. 4,890,199. When using such shields, it is very important that the conductive surface of the housing portion be reliable connected to signal ground. For the foregoing reasons, there is a need for electromagnetic shielding apparatus for cellular telephones and other electronic equipment, which reliably shields circuitry therein which is subject to electromagnetic interference from internally and externally generated electromagnetic signals.